JPH0254018B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for manufacturing a squirrel cage rotor, in which end rings and conductors are die-cast on a rotor core made of a laminated core.

Technical Background of the Invention Conventionally, the method shown in FIG. 1 has been used to manufacture this type of squirrel cage rotor. That is, in FIG.
1 is a movable type, 2 is a fixed type, and includes a recess 5 having a depth d into which the rotor core 4 is inserted into the movable insert 3 fitted into the movable mold 1, and an annular recess 7 for forming an end ring 6. is provided, and a rotor shaft 9 is attached to a push rod 8 slidably inserted into the insertion hole 3a of the movable insert 3.
In addition, the fixed mold insert 10 fitted into the fixed mold 2 is provided with an annular recess 12 for forming the end ring 11, a recess 13 for inserting the rotor shaft 9, and a molten metal insert. A side gate 14 is provided for injecting from the direction perpendicular to the axis.

Problems with the Background Art However, since the rotor core 4 is formed by laminating a plurality of punched steel plates, there is some variation in the thickness dimension D, and when inserted into the recess 5, D=d±Δd. The end face 4a of the rotor core 4 is fixed type 2
The fixed mold 2 protrudes by a dimension Δd from the parting line P of the movable mold 1, or vice versa.
It is in a depressed state. Therefore, if the end surface 4a of the rotor core 4 protrudes from the parting line P, a gap of Δd will be created between the fixed mold 2 and the movable mold 1 when the molds are closed. When molten metal is injected from the end ring 11, burrs are generated along the end surface 4a in the outer circumferential direction of the end ring 11,
In addition, the end face 4a of the rotor core 4 is depressed from the parting line P in the fixed type 2 and the movable type 1.
When the mold is closed, a gap of Δd will be created between the mold and the end surface 4a, so when the molten metal is injected from the side gate 14, burrs will be generated that cover the end surface 4a and even the opposite end surface 4b. All of these burrs are along the end surface 4a of the rotor core 4, and it is difficult to completely remove the burrs, and the remaining burrs may cause problems such as deterioration of motor startup noise and characteristics. Ta.

Purpose of the Invention The present invention has been made in view of the above circumstances, and its purpose is to enable end rings and conductors to be molded onto a rotor core by die-casting without generating burrs, thereby eliminating the troublesome burr removal work. To provide a method for manufacturing a squirrel cage rotor that can eliminate the need for motor startup noise and completely prevent adverse effects on motor characteristics.

Summary of the Invention The present invention provides elasticity in the thickness direction of a rotor core made of a laminated core so that the split mold can always be tightly closed at parting lines provided at positions facing the outer periphery of the rotor core. This is characterized in that a movable insert is provided in the split mold, and the movable insert is provided with elastic force by a deformable elastic body to clamp the rotor core in the thickness direction.

Embodiment of the Invention An embodiment of the invention will be described below with reference to FIG. 15 is a fixed type 16 and a movable type 17
A fixed mold insert 1 fitted into a fixed mold 16 is a split mold formed by dividing the two along the parting line P.
Into 8 are inserted a recess 19 into which the rotor core 4 is inserted, the depth being approximately half the thickness of the rotor core 4, an annular recess 20 for forming the end ring 11, and the rotor shaft 9. Recesses 21 are provided, respectively.
Furthermore, a pinpoint gate 22 communicating with the inner wall of the annular recess 20 is provided in the axial direction. Reference numeral 23 denotes a movable mold insert fitted into the movable mold 17, in which a recess 24 having an inner diameter equal to the outer diameter of the rotor core 4 is formed, and an annular insert for forming the end ring 6 in the recess 24. Movable insert 26 having a recess 25
is slidably provided, and a plurality of elastic bodies, for example, annular leaf springs 27, are inserted between the back wall of the recess 24 and the movable insert 26. Reference numeral 28 denotes a push rod slidably inserted into the insertion hole 26a of the movable insert 26 through the insertion hole 23a provided in the movable insert 23, and a recess 28a into which the rotor shaft 9 is inserted.
is provided. The rotor core 4 is, for example, a laminated core made by laminating a plurality of punched steel plates each having a plurality of open slots 29 formed in the outer periphery thereof.

Next, the operation of this embodiment configured as above will be explained. First, the movable mold 17 is moved in the direction of arrow A to open the mold, and the rotor core 4 into which the rotor shaft 9 is press-fitted is inserted into the recesses 19 and 2 of the fixed mold 16.
1, and then move the movable mold 17 in the direction opposite to arrow A and close the mold. First, the rotor shaft 9
is inserted into the recess 28a, and then the movable insert 26
comes into contact with the end surface 4b side of the rotor core 4. From this state, the movable insert 26 is in contact with the end surface 4b of the rotor core 4 while the movable mold 17 is moved in the opposite direction of arrow A until it comes into close contact with the fixed mold 16 at the parting line P. The leaf spring 27 remains stationary and is elastically deformed in the compression direction. Therefore, in the closed mold state where the movable mold 17 is in close contact with the fixed mold 16, the elastic force stored in the leaf spring 27 deforms the rotor core. The end face 4a of the rotor core 4 comes into pressure contact with the back wall of the recess 19, and the end face 4b comes into pressure contact with the movable insert 26.The variation in the thickness dimension D of the rotor core 4 is caused by the difference in the amount of elastic deformation of the leaf spring 27. The rotor core 4 is absorbed by the inner wall of the recess 19 and the movable insert 2.
It is held between 6 and 6. After mold closing is completed in this way, molten aluminum is pumped into the split mold 15 from the axial pinpoint gate 22, and the annular recess 25, open slot 29, and annular recess 20 are filled with the molten aluminum. After cooling and solidifying, the end rings 6, 11 and the conductor 30 located in the open slot 29 are integrally molded. Then, when the movable mold 17 is moved in the direction of arrow A to open the mold after completion of molding, the rotor core 4 is first moved in the direction of arrow A together with the movable mold 17, so that the narrow diameter portion of the pinpoint gate 22 When the gate is automatically cut and the movable mold 17 moves a certain length in the direction of arrow A, the movable mold 17 is further moved in the direction of arrow A with the movement of the push rod 28 being regulated, and the rotor core 4 is moved into the recess 24. be escaped from.

According to the method described above, the rotor core 4
The variation in the laminated thickness is absorbed as a difference in the amount of elastic deformation of the leaf spring 27, so that the end surface 4a of the rotor core 4 comes into pressure contact with the inner wall of the recess 19, and the end surface 4b The fixed mold 1 is pressed into contact with the child 26.
6 and the movable mold 17 are in close contact with each other at the parting line P, the end rings 6 and 11
inner and outer circumferential parts and parting line P
No burrs are formed on any part of the motor, and therefore, troublesome deburring work is completely unnecessary, and the adverse effects of burrs on the motor's starting noise and characteristics can be completely prevented.

Furthermore, since a pinpoint gate 22 from the axial direction is used in place of the conventional side gate 14, it is possible to automatically cut the gate, but the gate method may be selected appropriately. A coil spring or other elastic body may be used instead of the leaf spring 27.

By the way, conventionally, when the rotor core was not an open slot but a closed slot, a dividing line between the fixed type and the movable type was provided on the outer periphery of the rotor core, and when the mold was closed, the fixed type and the movable type were separated. It is also possible to deal with variations in laminated thickness of the rotor core by ensuring that there is a gap between . However, in the method of the present invention, the fixed mold 16 and the movable mold 17 are reliably brought into close contact with each other at the parting line P, so that it is suitable for open slots and can also be applied to other closed slots.

Effects of the Invention As is clear from the above description, the present invention can die-cast end rings and conductors on a rotor core without generating burrs, eliminates the need for troublesome deburring work, and improves the performance of motors. It is possible to provide a method for manufacturing a squirrel cage rotor that completely prevents startup noise and adverse effects on characteristics.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a conventional mold, and FIG. 2 is a vertical cross-sectional view of a mold showing an embodiment of the present invention. In the drawing, 4 is a rotor core, 6 and 11 are end rings, 9 is a rotor shaft, 15 is a split type, 16 is a fixed type, 17 is a movable type, 18 is a fixed insert, 22 is a pinpoint gate, 23 is a movable insert, 26 is a movable insert, 27 is a leaf spring (elastic body), 29 is an open slot, and 30 is a conductor.

Claims (1)

[Claims] 1. A rotor core made of a laminated core is inserted into a split mold in which a parting line is set at a position facing the outer periphery of the rotor core, and end rings and conductors are formed by die-casting. , the rotor is slidably provided on one of the split molds and is moved in one direction after molding to press approximately the center of the end face of the rotor core and push the rotor out of the one of the split molds. a push rod, a movable insert slidably disposed inside one of the split molds and positioned around the push rod, and a resilient force directed to the movable insert toward the other of the split molds. an elastic body that imparts a A squirrel-cage rotor characterized in that the laminated iron core is sandwiched in the thickness direction between the nest and the other of the split molds, and die-casting is performed by injecting molten metal into the split molds in such a sandwiched state. manufacturing method. 2. The method for manufacturing a squirrel cage rotor according to claim 1, characterized in that the molten metal is injected into the split mold through a pinpoint gate.